Thanks for checking, Emufan. Both Left Alt + RMB and Right Alt + RMB work for animpainting in FS-UAE over here. It's the darn Alt + LMB that doesn't work, and that's the most important animpainting function, because if you're using an animbrush (animated brush) with multiple colors, you can only animpaint that using Alt + LMB. Alt + RMB erases while animpainting.

I guess I'll wait until Frode hopefully reacts to my Github entry or to one of the discussions at this forum. In the mean time I'll look into ways of running WinUAE on MacOS via virtualization.

If you run into trouble with HTTP downloading, I can recommend JDownloader. It's a free, open source download manager. Works like a charm. You can also download just about any stream with it (YouTube, Soundcloud, you name it).